Equations of lines and connecting the Triumverate (equations to tables to graphs to tables to equations to...) can be tricky. Fortunately, there are some great resources out there.
A revision guide of what you need to know from Unit 5 from the CHRHS Learning Center
A revision guide of what you need to know from Unit 5 from the CHRHS Learning Center
ThatQuiz problems
For the visual learner, videos from The Khan Academy. Type the topic in the Search box in the upper right and watch.
Also for the visual learner, these nice slow explanations (audio and visual!) of some basic line questions are great.
For those looking for a very readable explanation other than the text, Megan from Purplemath explains things similarly to me.